Prosecutors said Anthony Murgio, 31, of Tampa, and Yuri Lebedev, 37, of Jacksonville, used their bitcoin exchange to aid criminal transactions, first hiding its dealings behind a website called Collectables.com, and later in a credit union for low-income residents they took over.

They did millions of dollars in business with thousands of customers, prosecutors said. The two were charged with conspiracy, operating an unlicensed money transmitting business and money laundering. They were taken into custody in Florida, officials said.